Major Features of IPv6

The defining feature of IPv6 is increased address space in comparison to IPv4.
IPv6 also improves Internet capabilities in numerous areas, as outlined in this section.

Expanded Addressing

IP address size increases from 32 bits in IPv4 to 128 bits
in IPv6, to support more levels of addressing hierarchy. In addition, IPv6 provides many
more addressable IPv6 systems. For more information, see IPv6 Addressing Overview.

Address Autoconfiguration and Neighbor Discovery

The IPv6 Neighbor Discovery (ND) protocol facilitates the autoconfiguration of IPv6 addresses. Autoconfiguration is the ability
of an IPv6 host to automatically generate its own IPv6 address, which makes
address administration easier and less time-consuming. For more information, see IPv6 Address Autoconfiguration.

The Neighbor Discovery protocol corresponds to a combination of these IPv4 protocols: Address
Resolution Protocol (ARP), Internet Control Message Protocol (ICMP), Router Discovery (RDISC), and ICMP
Redirect. IPv6 routers use Neighbor Discovery to advertise the IPv6 site prefix. IPv6
hosts use Neighbor Discovery for various purposes, which include soliciting the prefix from an
IPv6 router. For more information, see IPv6 Neighbor Discovery Protocol Overview.

Header Format Simplification

The IPv6 header format either drops or makes optional certain IPv4 header fields.
This change keeps the bandwidth cost of the IPv6 header as low
as possible, despite the increased address size. Even though IPv6 addresses are four times
longer than IPv4 addresses, the IPv6 header is only twice the size of
the IPv4 header.

Improved Support for IP Header Options

Changes in the way IP header options are encoded allow for more
efficient forwarding. Also, IPv6 options have less stringent limits on their length. The changes
provide greater flexibility for introducing new options in the future.

Application Support for IPv6 Addressing

Many critical Oracle Solaris network services recognize and support IPv6 addresses, for example: